Method of producing a metal coating of uniform thickness by spraying



Dec. 2, 1958 J. B. BRENNAN 2,862,837 METHOD OF PRODUCING A METAL COATINGOF UNIFORM THICKNESS BY SPRAYING Original Filed Feb. 27. 1952 A rra/a/v5 United States Patent METHOD OF PRODUCING A METAL COATING OF UNIFORMTHICKNESS BY SPRAYING Joseph B. Brennan, Cleveland, OhioC02l17fil1f9a20n t ifhapplicalltion Set-gal N 0. 273,594, February is aication e tember 9 1955 S 1 Ni. 533,414 pp p em 19 Claims. (Cl. 117-4)spray means.

Heretofore there have been various methods proposed for the productionof thin, porous metal sheets or strips such as are used in theproduction of various types of electrical condensers. Usually, in theproduction of strips of this type, a porous gauze or paper base strip isused onto which metallic particles are sprayed to deposit metal on thebase strip and form therefrom the continuous, elongate porous metalstrip that has desirable properties for use in condenser manufacture.

One difiiculty in producing the condenser forming strips is that thesprayed metal particles do not deposit uniformly on the base stripbecause the sprayed particles tend to be more densely distributed in thecenter part of the spray zone than at the marginal portions of the sprayzone. Also, in many instances, the marginal portions of the zone orfield of sprayed metal pass outside of or beyond the edges of the basestrip and are wasted and only the center portions of the spray zoneproduce a deposit on the base strip. Even if attempts are made tosalvage the sprayed metal that does not deposit upon the base strip,still such metal must be reprocessed, or at least must be sprayed againin order to effect a utilization thereof.

The general object of, the present invention is, therefore, to provide anovel method of depositing metal particles so as to efliciently andeconomically form a metallic strip which is of a substantially uniformthickness gauge transversely of the strip.

Another object of this invention is to provide a novel method ofdepositing sprayed metal particles on a base strip in whichsubstantially all of the sprayed particles, including those in themarginal portions of the spray zone, are deposited on the base strip andwherein the application of the sprayed metal particles to the base stripis carried out as a substantially continuous operation and produces adeposit which is of a substantially uniform thickness transversely ofthe strip.

A further object is to provide a novel method of producing a sprayedmetal strip of a uniform thickness in which successive passes of a basestrip, with component portions thereof in different positioningsrelative to spray delivered metal having spray zone portions comprisingthickly and thinly distributed particles, produce deposits having anaggregate desired uniform thickness transversely of the strip.

Still another object is to provide a novelv method of producing asprayed metal strip of a uniform thickness in which a base stripcomprising two longitudinally contiguous strip elements is sprayedsubstantially centrally thereof by successive spray fields havingportions comprising thickly and thinly distributed particles and inwhich said strip elements are parted and repositionedin a reversededge-abutting relation between the successive passes through the sprayfields.

The foregoing and other objects and advantages of the invention will bemade apparent as the specification proceeds.

This application is a continuation-in-part of application Serial No.15,474, filed March 17, 1948, now abandoned, and is also a continuationof application Serial No. 273,594, filed February 27, 1952, nowabandoned.

Reference is made to, the accompanying drawings wherein:

Fig. 1 is a plan view illustrating one portion of the spraying operationof this novel method for producing a spray-deposited metal strip of auniform thickness gauge;

Fig. 2 is a similar plan view illustrating another portion of thespraying operation;

Fig. 3 is a diagrammatic view further illustrating the present methodand showing in elevation one arrangement of apparatus by which themethod can be carried out; and

Fig. 4 is a diagrammatic showing of the same apparatus as a plan viewthereof.

Proceeding now with a more detailed description of the invention, Figs.1 and 2 show a base strip 10 being moved in successive passes through aspray field composed of metal particles P for producing a deposit 11 ofthe sprayed metal on the base strip to constitute a metal sheet or striphaving a uniform thickness gauge transversely of the base strip. Thespray field for the first. pass is produced by a suitable spray nozzle12 of a conventional construction and having a nozzle opening 12 facingtoward the base strip 10. The spray field for the second pass can beproduced by the nozzle 12 or by a second conventional nozzle 13 which issubstantially identical with the nozzle 12 and has a nozzle opening 13facing toward the base strip. The spray field produced by the nozzles 12and His of the kind comprising a stream of the metal particles P inwhich the. metal particles occur in a relatively thickly distributedrelation in the portion or zone surrounding the central axis of thestream and in a relatively thinly distributed relation around themarginal portions of the stream.

As shown in Figs. land 2, the base strip 10 is a relatively wide stripcomprising two longitudinally coextending component strip elements 14and 15 having a common inner edge line 16 which is located substantiallyat the longitudinal center line of the base strip. In this instance, thestrip elements 14 and 15 are separate individual narrow strips havingtheir inner or adjacent longitudial edges in meeting or abuttingrelation and defining the common inner edge line 16. The base strip 10and the strip elements 14 and 15 thereof preferably comprise a porousbase strip material, such as a porous paper or gauze.

The spray nozzles 12 and 13 are disposed relative to the base strip 10such that the central axis of the spray field or fields being producedthereby is substantially perpendicular to the plane of the base stripand intersects such strip substantially on the longitudinal center linethereof. In accordance with the present invention, the spray fieldproduced by the spray nozzles is narrower in width than the base strip10 and when directed against the base strip in the relation justmentioned, all of the particles P of the spray field will fall withinthe outer side edges of the base strip and will be deposited on the basestrip and substantially none of the particles will be wasted by passingbeyond the outer edges of the base strip.

The metal deposit formed on the base strip 10 by each of the nozzles 12and 13'will be produced primarily along 3 the longitudinal center lineof the base strip, that is to say, on the adjacent inner edge portionsof the coextending strip elements 14 and 15. The spray deposited metalappliedto the base strip by each nozzle will be relatively thick alongthe center portion-of the base strip and will be relatively thinalongt'he outer edges of the deposit. In other words, the layer of spraydeposited metal applied to the base strip by each of the nozzles 12 and13 will be of a somewhat tapering thickness transversely of the basestrip having its maximum thickness produced by the dense center portionof the spray field and located at or adjacent the longitudinal centerline of the base strip and having relatively thin outer edge portionslying inwardly of the extreme outer edges of the strip elements 14 and15 and formed by the relatively thin outer-peripheral portion of thespray field. I

After the base strip hasbeen sprayed centrally thereof by the spraynozzle 12, as shown in Fig. l, the component strip elements 14 and areparted along the longitudinal common inner edge line 16 and arerearranged in acoextending longitudinally contiguous relation for thesecond passage of the base strip 10 through. the spray field, that is,past the spray nozzle 13. In the rearrangement of the strip elements 14and 15 their original outer edges 14 and 15 are located in abuttingengagement such that these original outer edges now form the commoninner edge line 16 which is located substantially at the longitudinalcenter line of the base strip. As shown in Fig. 2, the base strip formedby the rearranged strip elements 14 and 15 has the relatively thicklydeposited metal located along their then outer edges and have theirthinly coated, or uncoated portions, extending along the longitudinalcenter line of the base strip.

During the second passage of the base strip 10 through the spray field,that is past the nozzle 13 as shown in Fig.

2, the relatively thick portion of the metal layer then being formedwill be applied to the previously uncoated or thinly coated centralportion of the base strip and the relatively thin edge portions of thelayer then being formed will be applied in overlying relation to thethick portions of the previously applied metal deposit. The two metallayers of tapering thickness thus applied to the base strip during itssuccessive passes through the spray field will aggregate a single layeror metal strip of a substantially uniform thickness transversely of thebase strip.

Instead of the base strip 10 being composed of separate individualnarrow strips as mentioned above and as shown in Figs. 1 and 2, it maycomprise two such coextending longitudinally contiguous strip elementshaving a com.- mon inner edge line and which elements constituteintegrally connected portions of a single relatively wide base strip.When such a relatively wide base strip is used in carrying out thepresent method, the coextending strip elements are parted by cuttingthewide base strip longitudinally thereof along its center line, followingthe first passage of the base strip through the spray field and prior tothe above-described rearrangement of the strip elements for the secondpassage of the base strip through the spray field.

Figs. 3 and 4 show a method similar to that already described above butbeing carried out as a continuous operation and with the sprayed metalbeing applied to both faces of the base strip. Figs. 3 and 4 also showone embodiment of apparatus suitable for carryingout this form of themethod. Although Figs. 3 and 4 disclose the application of the sprayedmetal to both faces of the base strip, the invention also contemplatescarrying out the method by applying the sprayed metal to one face onlyof the base strip and to the use of a base strip formed either byseparate narrow strips or by integrally connected coextending stripelements.

As shown in Figs. 3 and 4, a relatively wide base strip 17, beingwithdrawn from a roll 18, passes in succession over suitably drivenbacking rollers or mandrels 19 and 20. During the passage of the basestrip around these rollers, sprayed metal is deposited on both faces ofthe base strip by spray nozzles 21 and 22 which are of a conventionalform. The spray nozzles 21 and22 deliver streams of metal particlesconstituting spray fields of the same characteristics as the sprayfields produced by the nozzles 12 and 13 and described above, and causesimilar metal deposits of a tapered thickness to be applied to the basestrip primarily along the longitudinal center portion thereof.

From the rollers 20, the centrally coated base strip 17 then passesaround a guide roller 23 and under a slitting wheel 24 which is suitablydriven and by which the wide base strip 17 is out along its longitudinalcenter line 25 and divided into two longitudinally coextending stripelements in the form of separate narrow component strips 26 and 27.

The two narrow component strips 26 and 27 are led through a turningdevice 28 comprising longitudinally spaced pairs of horizontallydisposed guide rollers 29 and 3t and two pairs of vertically disposedturning rollers 31 and 32 located between the pairs of guide rollers.The strip element 26 extends between the pair of turning rollers 31 andthe strip element 27 extends between the pair of turning rollers 32.During the passage of the narrow strips 26 and 27 through the turningdevice 28, the strips will be twisted in an angular relation andrearranged in a longitudinally contiguous coextending relation to form asimilar wide base strip 17. During their travel from the guide rollers29 to the turning rollers, the narrow strips are twisted throughapproximately and during their travel from the turning rollers to theguide rollers 30, the narrow strips are further twisted through a second90 in the same direction to thereby invert the narrow strips.

By the above-described parting and twisting of the narrow strips 26 and27, they will be rearranged in longitudinally contiguous relation withtheir original outer edges 26 and 27 in abutting relation to form thesimilar Wide base strip 17 in which the then abutting outer edges definea common inner edge line 33 located substantially at the longitudinalcenter line of the base strip.

In this new or similar base strip 17 the previously applied sprayedmetal deposit will have its portions of maximum thickness located alongthe outer edges of the narrow strips 26 and 27 and the central portionof the new base strip will be uncoated or only relatively thinly coated.The condition of the base strip 17 will be similar to the condition ofthe base strip 10 as described above in con nection with Fig. 2, afterthe rearrangement of the component strip elements but prior to itssecond passage through the spray field.

The new base strip 17 is then led around suitably driven backing rollersor mandrels 35 and 36 and past a second pair of spray nozzles 37 and 38.The spray nozzles 37 and 38 are substantially identical with the nozzles21 and 22 and function in the same manner to apply a second deposit ofsprayed metal to opposite faces of the base strip 17 by directing thespray fields primarily against the central portion of the strip. Thesprayed metal deposit produced by the nozzles 37 and 38 corresponds withthe spray deposit produced by the spray nozzle 16 of Fig. 2 anddescribed above, that is to say, the spray nozzles 37 and 38 produce asecond layer of sprayed metal on the base strip by covering the uncoatedor thinly coated central portion with a relatively thick deposit andapplying arelatively thin deposit over the thick portions of the firstlayer.

The sprayed metal deposit thus produced by the method and apparatus ofFigs. 3 and 4 will be one in which the two layers of tapering thicknessapplied to each face of the base strip will aggregate a layer on eachface which is of uniform thickness transversely of the base strip.

In the method illustrated in Figs. 3 and 4 and described above, the basestrip 17 is a relatively wide strip which is cut longitudinally toseparate the two component strip elements 26 and 27 thereof. Instead ofusing such a wide base strip and cutting the same longitudinally, themethod can be carried out by using a similar relatively wide base stripformed of two component strip elements comprising separate individualnarrow strips having their adjacent edges in meeting relation anddefining a common inner edge line at the longitudinal center of the basestrip. When the base strip is composed of two strip elements comprisingseparate individual narrow strips as just explained, the cutting wheel24 is omitted.

Metal coated base strips produced in accordance with this invention havegreater electrical capacity than corresponding strips produced inconformity with the prior art. For example, coated base strips producedin accordance with the present invention have shown capacities ofbetween 7.8 and 8.1 microfarads per 6 square inches of material, whereascorresponding areas of base strips produced by other known methods havecapacities of only between and 6 microfarads. Both base strips wereproduced by use of the same amount of sprayed material with thedifference being that by practice of this novel method, an elficientutilization of the spray ma terial was achieved. By previous sprayingmethods much of the metal travels beyond the edges of the base strip andis not utilized in forming the deposit, whereas in the present methodthis additional metal is deposited on the base strip and is utilizedprimarily on the edge portions thereof to produce a deposit of uniformthickness. This has appreciably benefited the electrical capacity of theresultant strip material. Electrode sheets made in accordance with theprior art have edge portions which are thinner than their centersections and these thinner edge portions have more resistance than thecenter sections. A condenser made from an electrode sheet of suchvariable thickness has a greater power-factor loss than a condenser madefrom a uniform gauge electrode strip, such as the one produced by thepresent invention.

Although it has been indicated at a previous point in this applicationthat the base strip may be formed from paper, gauze or other suitablematerial, the present invention also contemplates depositing the sprayedmetal onto a metal tape. The spray deposited metal may be permitted toremain on such tape, or can be stripped therefrom as a sheet after thesprayed metal has solidified. In such latter instances, it may benecessary to treat the metal tape in known manners to prevent adhesionof the deposited metal to the base metal tape. Another possibility inproducing a sprayed metal strip in accordance with this invention, isthat of forming a spray deposit of metal on a fibrous base strip afterwhich the excess portion, or all exposed material of the fibrous basestrip, is burned off or otherwise removed from the resultant strip.

Sprayed metal strips made in accordance with this invention generallyare, for example, about two-inches in width and have a thickness ofabout .0035 inch. Similar strips made in accordance with prior sprayingpractices have varied appreciably (percentage-wise) in thickness at theedges of the strips and have had a thickness of only about .0025 inch atthe edge portions. However, by practice of the present invention whereinthe edge portions of a base strip are subjected to a principal and to asecondary spraying action, the base strip produced has a substantiallyuniform thickness laterally of the strip. Furthermore, the stripproduced will be uniform in thickness, width and other properties andcharacteristics at longitudinally spaced portions thereof. When producedby the present method, the strip can therefore be held to very closetolerances and will be of a uniform gauge both longitudinally andtransversely.

From the foregoing detailed description and the accompanying drawing, itwill now readily be understood that this invention provides a novelmethod of spraying metal onto a base strip by which an interstitiallyporous deposit of metal will be produced efliciently and economically onsuch base strip having a substantially uniform thickness transversely ofthe strip. Additionally, it will be seen that the present inventionprovides for the carrying out of the novel method as a continuousoperation and with an eflicient use of the sprayed metal. It will alsobe seen that the parting and rearrangement of the component stripelements of a relatively wide base strip, as provided by this invention,permits the use of conventional spray nozzles since the spray depositsproduced by such conventional nozzles are utilized in a reverselytapering relation to aggregate a spray deposit of uniform thicknesstransversely of the strip.

Although the present invention has been disclosed herein to a somewhatdetailed extent, it will be understood, of course, that the invention isnot be regarded as being limited correspondingly in scope, but includesall changes and modifications coming within the terms of the claimshereof.

Having thus described my invention, I claim:

1. In a method of spraying metal onto a base strip the steps of,advancing a'base strip, creating a spray field of molten metal anddirecting the same toward the longitudinal center line of said basestrip, parting said base strip alongsaid longitudinal center line andrearranging the resulting strip elements with the original outer edgesthereof in substantially longitudinally abutting relation, and directingthe spray field toward the longitudinal meeting line of the rearrangedstrip elements of the advancing base strip. i

2. That method of spraying molten metal onto a base strip moved withrelation to the sprayed metal to effect eificient deposit of the metalthereon comprising, moving a relatively wide base strip with relation toa relatively narrow field of sprayed molten metal particles to depositmetal primarily on the center portion of the strip, longitudinallyseparating the strip at approximately its center, abutting the originalouter edges of the strip, and moving the abutted original outer edges ofthe strip with relation to the field so that they pass into and throughthe spray field substantially at the center thereof to deposit thesprayed molten metal primarily on the then center portion of the strip.

3. That method of spraying molten metal onto a base strip moved throughthe sprayed metal to effect efficient deposit of the metal thereoncomprising, moving a relatively wide base strip longitudinally through arelatively narrower field of sprayed molten metal particles to depositsubstantially all of the sprayed metal on the strip and primarily on thecenter portion thereof, longitudinally separating the strip at itscenter portion, associating the original outer edges of the strip, andthen moving the strip longitudinally through such relatively narrowerspray field with the associated original outer edges of the strippassing into and through the spray field substantially at the centerthereof to deposit all of the sprayed metal on the strip and primarilyon the then center portion thereof.

4. In a method of spraying metal onto a base strip the steps of,advancing a base strip comprising two longitudinally coextendingcomponent strip elements having a common inner edge line substantiallyat the longitudinal center line of the base strip, creating a sprayfield of molten metal and directing the same against said base stripwith the central axis of the spray field substantially intersecting saidcommon inner edge line, parting said strip elements along said commoninner edge line and rearranging said strip elements with the originalouter edges thereof in substantially abutting relation along alongitudinal meeting line, and directing the spray field toward thelongitudinal meeting line of the rearranged strip elements and againstthe advancing base strip with the central axis of the spray fieldsubstantially intersecting said longitudinal meeting line.

S. In a method of spraying metal onto a base strip the steps of,advancing relatively wide base strip material comprising two componentstrip elements in coextending longitudinally contiguous relation andhaving a common inner edge line substantially at the longitudinallycenter line of the wide base strip material, projecting spray deliveredmolten metal defining central and peripheral spray zone portionscomprising densely and thinly distributed particles respectively, andexposing the base strip material to said spray delivered metal in twosuccessive passes with the central spray zone portion directed towardsaid common inner edge line and with said peripheral spray zone portionsfalling within the outer edges of said wide base strip material andduring said successive passes forming first and second deposit layers onsaid base strip material which are of a tapering thickness transverselyof the base strip material and are reversely disposed with thickportions of the second deposit layer overlying thin portions of thefirst deposit layer and with thin portions of the second deposit layeroverlying thick portions of the first deposit layer such that saiddeposit layers aggregate a spray deposited metal strip of asubstantially uniform gauge thickness transversely thereof.

6. In a method of spraying metal onto a base strip the steps of,advancing a base strip, creating a spray field of molten metal ofvarying intensity and having a maximum density adjacent the central axisof the spray field and a minimum density at the outer edge of the sprayfield, directing said spray field against said base strip with thecentral axis of the spray field substantially intersecting thelongitudinal center line of said base strip and with the outer portionsof the spray field falling within the outer edges of said base strip andforming on said base strip a first deposit layer of the sprayed metalwhich is of decreasing thickness from said longitudinal center linetoward said outer edges, parting said strip along said longitudinalcenter line into two strip elements and rearranging said strip elementswith the original outer edges thereof in substantially abutting relationalong a longitudinal meeting line, and directing the spray field towardsaid longitudinal meeting line of the rearranged strip elements andagainst the advancing base strip formed thereby with the central axis ofthe spray field substantially intersecting said longitudinal meetingline and with the outer, portions of the spray field falling within thetheir outer edges of said base strip and forming on the base strip asecond deposit layer of the sprayed'metal which is of decreasingthickness from said longitudinal meeting line toward said then outeredges, said first and second deposit layers forming an aggregate depositlayer having a substantially uniform thickness transversely of the basestrip.

7. The method of spraying molten metal onto a base strip as defined inclaim 6, in which the spray field is directed against both faces of thebase strip prior to the step of parting said base strip, and in whichthe spray field is again directed against both faces of the base stripsubsequent to said step of rearranging said strip elements.

8. That method of spraying molten metal onto a' base strip moved throughthe sprayed metal to efiect efiicient deposit of the metal thereoncomprising, associating two component base strips in edge to edgerelation to form a composite base strip, moving the composite base stripthrough a relatively narrow field of sprayed molten metal particles todeposit metal primarily on the center portion of the composite strip,separating the component strips of the composite strip, abutting theoriginal outer edges of the component strips, and moving the abuttedoriginal outer edges of the component strips into and through the fieldat the center thereof to deposit the sprayed metal primarily on the thencenter portion of the composite strip.

9. That method of efficiently utilizing metal in a molten metal sprayfield comprising the steps of, moving a relatively wide composite basestrip formed of two coextending longitudinally contiguous sections ofrelatively narrow strip through a molten metallic particle spray fieldnarrower than the composite base strip, which spray field is-of'varyingintensity laterally thereof to deposit metal on said base strip in alaterally non-uniform layer thickness, parting and rearranging thesections of narrow strip to provide a similar composite base striphaving the original outer edges of the sections of narrow strip now inlongitudinally contiguous relation substantially at the longitudinalcenter line of said similar base strip, and passing said similar basestrip through the spray field again to deposit a second metal layerthereon and produce a substantially uniform thickness deposit on eachnarrow strip.

10. In a method of spraying metal onto a base strip the steps of,advancing a relatively wide base strip, creating a spray field of moltenmetal of varying intensity and having a maximum density adjacent thecentral axis of the spray field and a minimum density at the outer edgeof the spray field, directing said spray field against said base stripwith the central axis of the spray field substantially intersecting thelongitudinal center line of the base strip and with the outer edges ofsaid spray field falling within the outer edges of said base strip andforming on said base strip a first deposit layer of the sprayed metalwhich is of decreasing thickness from said longitudinal center linetoward said outer edges, severing said base strip longitudinally alongsaid center line to form two relatively narrow strips, rearranging saidnarrow strips with the original outer edges thereof in substantiallyabutting relation along a longitudinal meeting line, and directing thespray field toward said longitudinal meeting line of the rearrangedstrip elements and against the advancing base strip formed thereby withthe central axis of the spray field substantially intersecting saidlongitudinal meeting line and with the outer portions of the spray fieldfalling within the then outer edges of said base strip and forming onthe base strip a second deposit layer of the sprayed metal which is ofdecreasing thickness from said longitudinal meeting line toward saidthen outer edges, said first and second deposit layers forming anaggregate deposit layer having a substantially uniform thicknesstransversely of the base strip.

11. The method of spraying molten metal onto a base strip as defined inclaim 10, in which the spray field is directed against both faces of thebase strip prior to the step of severing the base strip into said narrowstrips, and in which the spray field is again directed against bothfaces of the base strip subsequent to said step of rearranging thenarrow strips.

12. A method of producing a molten spray deposited continuous metalstrip having a uniform thickness gauge for all portions longitudinallyand transversely of such metal strip comprising the steps of, creating amolten metal spray field of varying density and composed of particles ofmetal of a given characteristic, subjecting a moving base strip to saidspray field with substantially all of the particles of said fieldfalling on said base strip and producing on said base strip a firstsprayed metal deposit having a relatively thick portion and a relativelythin portion, and thereafter again subjecting said base strip to such amolten metal spray field of varying density and composed of particles ofmetal of said given characteristic with substantially all of theparticles of said field falling on said base strip for producing asecond deposit thereon such that the relatively thin portion of thefirst deposit is exposed to a relatively dense portion of the sprayfield to build up the relatively thin portion of said first depositrapidly and the relatively thick portion of said first deposit isexposed to a relatively less dense portion of the spray field to buildup the relatively thick portion of the first deposit more slowly, theexposure of different portions of said first deposit to the subsequentspray application being correlated to produce a uniform thickness gaugedeposit on the base strip composed of particles of metal of said givencharacteristic.

13. A method of producing a metal strip according to claim 12 in whichthe axis of said spray field is substantially perpendicular to the basestrip and each spray deposit is of maximum density at the center thereofand gradually diminishes in density to the edges thereof.

14. A method of continuously producing metallic strip of substantiallyuniform thickness by spray deposit comprising moving a base strip at aconstant rate through a plurality of molten metal spray fields each of adensity varying in a plane substantially perpendicular to the axis ofthe field to subject at least one face of the base strip transverselythereof to a plurality of spray applications with substantially all ofthe particles of each spray field falling on said base strip and witheach application forming a deposit upon the base strip uniformlongitudinally of the strip and of varying density transversely thereof,a thin deposition resulting from one application being reinforced byanother application whereby a deposition of substantially uniform depthtransversely and longitudinally is provided.

15. A method of producing a molten spray deposited continuous metalstrip of uniform thickness comprising subjecting at least one surface ofa longitudinally moving base strip to a first spray application in amolten metal spray field of varying density transversely of the stripbut uniform longitudinally thereof and having an axis substantiallynormal to the strip and by it forming a thick deposit and a relativelythin deposit on the base strip with substantially all of the particlesof said spray field falling on said base strip, and thereaftersubjecting the same face of the base strip to a second similar sprayapplication so that the relatively thin deposit is exposed to arelatively dense spray field to build up the thin deposit rapidly andthe thick deposit is exposed to a relatively less dense spray field tobuild up the thick deposit slowly, the exposure of different sections ofthe original deposit to subsequent spray deposits being correlated toproduce a relatively uniform gauge deposit on the base strip.

16. A method of producing a molten spray deposited continuous metalstrip having a uniform thickness gauge for all portions longitudinallyand transversely of such metal strip comprising the steps of, creating amolten metal spray field of varying density and composed of particles ofmetal of a given characteristic, subjecting a moving base strip which iswider than the spray field to said spray field to deposit substantiallyall of the sprayed material thereon and primarily on the center portionof the base strip to produce a first sprayed metal deposit having arelatively thick portion at the center portion of the strip, parting thestrip longitudinally at approximately its center, abutting the originalouter edges of the strip to form a composite strip, and thereaftermoving the composite strip through a molten metal spray field of varyingdensity and composed of particles of metal of said given characteristicwhich is relatively narrower than the composite strip so thatsubstantially all the sprayed particles are deposited on the compositebase strip and primarily on the central portion of the composite basestrip to form a second deposit thereon such that the relatively thinportion of the first deposit is exposed to a relatively dense portion ofthe second mentioned spray field to build up the relatively thin portionof said first deposit rapidly and the relatively thick portion of saidfirst deposit is exposed to a relatively less dense portion of thesecond mentioned spray field to build up the relatively thick portion ofthe first deposit more slowly, the exposure of different portions ofsaid first deposit to the subsequent spray application being correlatedto produce a uniform thickness gauge deposit on the base strip composedof particles of metal of said given characteristic.

17. A method of producing metal strip according to claim 16 in which twoindividual base strips are located in edge to edge relation to form theoriginal base strip an two individual strips are separated after thefirst spray deposit and the original outer edges of the original basestrip abutted to form the composite base strip.

18. A method of producing a molten spray deposited continuous metalstrip having a uniform thickness gauge for irtions longitudinally andtransversely of such metal snip comprising the steps of, creating amolten metal spray field of varying density and composed of particles ofmetal of a given characteristic, subjecting a moving base strip ofporous fibrous material to said spray field with substantially all ofthe particles of said field falling on said base strip and producing onsaid base strip a first sprayed metal deposit having a relatively thickportion and a relatively thin portion, and thereafter again subjectingsaid base strip to such a molten metal spray field of varying densityand composed of particles of metal of said given characteristic withsubstantially all of the particles of said field falling on said basestrip for producing a second deposit thereon such that the relativelythin portion of the first deposit is exposed to a relatively denseportion of the spray field to build up the relatively thin portion ofsaid first deposit rapidly and the relatively thick portion of saidfirst deposit is exposed to a relatively less dense portion of the sprayfield to build up the relatively thick portion of the first deposit moreslowly, the exposure of dififerent portions of said first deposit to thesubsequent spray application being correlated to produce a uniformthickness gauge deposit on the base strip composed of particles of metalof said given characteristic.

19. The method of producing a particulate interstitially porous metalstrip deposit of a uniform thickness and width on a porous base stripcomprising, forming a molten-metal-particle spray field of variabledensity transversely of the base strip, successively passing said basestrip relative to said spray field While differently positioningcomponent portions of the base strip relative to each other, anddepositing substantially all of the particles of said spray field onsaid base strip during such successive passing and different positioningand thereby continuously producing such a metal strip deposit having anaggregate desired uniform thickness transversely of the strip deposit.

References Cited in the file of this patent UNITED STATES PATENTS2,036,329 Giles Apr. 7, 1936 2,159,704 Levey May 23, 1939 2,280,789Brennana Apr. 28, 1941 2,297,607 Blackburn Sept. 29, 1942 2,330,300MacDonald Sept. 28, 1943 2,560,411 Burns July 10, 1951 2,582,744 BrennanJan. 15, 1952 2,696,449 Ericks Dec. 7, 1954 2,697,671 Brennan Dec. 21,1954

1. IN A METHOD OF SPRAYING METAL ONTO A BASE STRIP THE STEPS OF,ADVANCING A BASE STRIP, CREATING A SPRAY FIELD OF MOLTEN METAL ANDDIRECTING THE SAME TOWARD THE LONGITUDINAL CENTER LINE OF SAID BASESTRIP, PARTING SAID BASE STRIP ALONG SAID LONGITUDINAL CENTER LINE ANDREARRANGING THE RESULTING STRIP ELEMENTS WITH THE ORIGINAL OUTER EDGES